We want to move a production application to a new server. If we copy all the application files, including the Harvest signature files to the new server, will they still be valid? Or will we need to delete them all and do a fresh check-out to the new server?

Answer:

When looking at the contents of a signature file, the exact client path to each item is recorded, but not the host name of the client server. So, as long as the folder structure is exactly the same, and the timestamps and permissions on the folders and files is exactly the same, this should work just fine.